Capsicum(hot red peppers) is the most widely used spicy material in the preparation of foodsand is also reported to have medicinal applications. Capsaicinoids and capsinoids are two different classesof lipophilic alkaloids present in capsicum(Kobata et al.
1998). Capsaicin, is anamide of vanillylamine with a fatty acid, is responsible for the pungent natureof the fruits of red pepper (Kawada et al. 1986). Capsinoids, on the other handare the nonpungent ester analogue of capsaicinoid. Anothertwo related compounds of coniferyl esters, capsiconiate coniferyl (E)-8-methylnon-6-enoate, anddihydrocapsiconiate coniferyl 8-methylnonanoate have been isolated from Capsicum baccatum L. var. praetermissum (Fig.
1). Capsiconinoids possess similarbiological activities like capsaicinoids and capsinoids (Kobata et al. 2008;Tanaka et al. 2009). However, their pungency was found to be much weaker thanthat of capsaicin, which has been attributed to the presence of double bondnext to the aromatic ring (Walpole et al.
1993). These food compounds werefound to be involved in the obesity prevention (Watanabe and Yerada 2015).Fewof the coniferyl esters of fatty acids were already isolated in the literature.Coniferyl esters of palmitic and oleic acids were isolated from Platycodon grandiflorum A. Decandolleroots. The antioxidant activities of these two compounds were found to be ashigh as butylated hydroxytoluene (BHT) or butylated hydroxyanisole (BHA) (Leeet al. 2004).
Appendino et al. (2004)isolated coniferyl stearate along with several furano- anddihydrofuranocoumarins from the roots and seeds of the poisonous tree, named Opopanax chironium L. Owingto the low pungency of the coniferyl esters with potential biological andantioxidant activity, it would be interesting to study the synthesis andevaluation of a series of coniferyl esters which was not studied earlier. Lipasecatalyzed synthesis of capsiconinoid analogues would be more favorable in the preparationof such biologically important molecules over chemical catalysis.
In additionlipases offer selectivity towards alcohols over phenols with mild reactionconditions which lead to high product yields and purity (Adlercreutz 2000; Kakiet al. 2012). Therefore, the present work aims at the enzymatic synthesis oflinear analogues of capsiconinoids and their evaluation for antioxidantactivities, which has not been reported earlier.